Mold with tie rod assembly for slotted block

ABSTRACT

In conjunction with a slab mold having spaced side blocks and a top, a bottom and end blocks engaged between the side blocks to define a casting cavity, an improved metallic end block is provided with a plurality of spaced, transverse slits. The end block is held in position relative to the other blocks by a supporting structure. A tie rod arrangement is secured to the upper and lower rearward portion of the end block to prevent vertical warping of the end block during the casting of a slab.

United States Patent Peck [ Sept. 5, 1972 [54] MOLD WITH TIE RODASSEMBLY FOR SLOTTED BLOCK [72] Inventor: Richard Otis Peck, c/o AmstedResearch Laboratory, 340 County Line Road, Bensenville, 111. 60106 22Filed: April 13,1971

21 Appl.No.: 133,604

[52] US. Cl ..249/82 [51] Int. Cl. ..B22d 7/00 [58] Field of Search.249/82, 158; 164/342; 202/268;

248/DlG. 1

[56] References Cited UNITED STATES PATENTS 3,544,058 12/1970 Lohman..249/l58X Primary Examiner-Robert D. Baldwin Attorney-Walter L.Schlegel, Jr. and John W. Yakimow [57] ABSTRACT In conjunction with aslab mold having spaced side blocks and a top, a bottom and end blocksengaged between the side blocks to define a casting cavity, an improvedmetallic end block is provided with a plurality of spaced, transverseslits. The end block is held in position relative to the other blocks bya supporting structure. A tie rod arrangement is secured to the upperand lower rearward portion of the end block to prevent vertical warpingof the end block during th casting of a slab.

' 7 Claims, 3 Drawing Figures MOLD WITH TIE ROD ASSEMBLY FOR SLOTTEDBLOCK BACKGROUND OF THE INVENTION This invention relates to moldconstruction and more particularly to a new and improved supportarrangement for use in conjunction with a slab mold.

A basic mold structure particularly suitable for easting slabs ofvarious sizes is described in U.S. Pat. No. 3,340,926. That moldstructure includes a plurality of inner graphite blocks interengagedbetween a pair of graphite side blocks to define a casting cavity.

One of the difficulties encountered in the use of such molds is thefragile nature of the graphite. The blocks may be easily chipped orbroken during assembly and disassembly of the mold. It was thereforesuggested in U.S. Pat. No. 3,544,058 that at least one of these graphiteblocks be replaced by a metallic block composed of a material such ascast iron or steel. For various reasons described within that patent,the block chosen was the bottom block. Since one portion of the bottomblock is exposed to molten metal while the other portion remainsrelatively cool, The block has a tendency to distort. The distortion iscaused by thermal expansion which results in the bowing up of the blockat its ends or middle, thereby causing hot tears or other defects in thecasting. The problem was corrected by providing means for limitingvertical warpage of the bottom block while permitting longitudinalexpansion.

It has subsequently been determined that metallic blocks may also beused for the end blocks and the top block of a mold structure. However,the warpage preventing means disclosed in U.S. Pat. No. 3,544,058 havenot been found equally suited for use on the top and end blocks.

BRIEF DESCRIPTION OF THE INVENTION Applicant has solved the aboveproblems and others by providing a metallic block usable in a slab moldstructure. The metallic block has a plurality of spaced slits startingat the rearward surface and extending toward the casting cavity. Theseslits are preferably in the neighborhood of three-fourths of the widthof the block.

Lugs are attached to the upper and lower rearward surface of the block.Tie rods are engaged with the lugs and are fastened to maintain thelongitudinal dimension of the rearward surface of the block. Adjustmentmeans are provided on the tie rods to either draw the upper and lowersurfaces closer together or permit them to expand longitudinallyrelative to each other.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side elevationalview taken through the casting cavity of a slab mold structure;

FIG. 2 is an enlarged side elevational view of the end block illustratedin FIG. 1; and

FIG. 3 is a sectional view taken at line 33 of FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a knownadjustable slab mold 10 having opposed side blocks 12 (only one shown).This mold is similar to the one illustrated in U.S. Pat. No. 3,544,058,issued on Dec. 1, 1970. Hydraulic or other suitable devices (not shown)are provided for moving the side blocks toward and away from each otherin a known manner. A plurality of inner blocks are interengaged betweenthe side blocks 12 and include a top block 14, a bottom block 16supported on a beam 18 and end blocks 20 and 22 which together define acasting cavity 24. The height of the casting cavity 24 may be varied byraising or lowering the top block 14 by any number of known means, e.g.,screws 26. The length of casting cavity 24 is also adjustable by meansof suitable power devices 28, such as hydraulic cylinders, which mayurge one end block 20 toward or away from the other end block 22.

In use molten metal is introduced under pressure from a pouring tube 30upwardly through an ingate 32 and into casting cavity 24. A suitableriser construction 34 communicates with the casting cavity 24 to feedshrinkage which would otherwise develop in the casting during cooling.

The invention resides in an improved inner block and is illustrated inreference to end block 20. It should be appreciated that top block 14,bottom block 16 and end block 22 may also be modified in a like manner.

As illustrated in FIGS. 2 and 3, end block 20 is an elongated unitarymember composed of a metal such as cast iron or carbon steel. Aplurality of slots 36 extend transversely through block 20 from the rearsurface 38 of the block forward toward the cavity defining surface a 40which is substantially flat and continuous. The slots 36 are spaced atintervals along substantially the entire height of block 20 and extendforwardly for more than half but less than the entire width of theblock. Preferably, the slots are in the neighborhood of threefourths ofthe width of block 20. Round holes 42 are located at the inward end ofeach slot 36 to relieve stress concentrations and to prevent tearing ofblock 20 during thermal expansion and contraction.

Shims, the same thickness as the opening of the slots, are located ineach slot 36. The shims are preferably the width of block 20 and extendfrom rear surface 38 to holes 42.

Means 44 are provided to resist thermal distortion of block 20 duringcasting. These means 44 may take the form of lugs 46 and 48 secured atthe upper and lower extremities of the rear surface 38 of block 20. Abolt 50 engaged with a washer 52 projects through an opening in upperlug 46 and is in threaded engagement with a center portion of a trunnion54. The trunnion 54 has opposed cylindrical arms 58 projecting throughopenings in opposed tie rods 60 and 62. The tie rods 60 and 62 extendalong the length of block 20 and terminate proximate lug 48 whichcomprises opposed shear blocks 64 and 66 outwardly spaced from a centershear block 68. A cylindrical pin 70 projects through openings in shearblock 64, tie rod 60, shear block 68, tie rod 62 and shear block 66. Asmall pin 72 may project through shear block 68 and pin 70 to preventmovement of pin 70 relative to components 60 through 68.

A metal plate 74 is located intermediate tie rods 60 and 62 and ispartially located within a groove 76 which extends along the length ofblock 20. Pins or bolts 78 intermediate spaced grooves 36 projectthrough openings in block 20 and elongated slots in plate 74 to retainplate 74 to block 20. Suitable power devices 28, previously described,are secured to plate 74 and are mounted to permit movement of block 20relative to the remaining inner blocks of mold 10.

In operation, end block 20 is located in casting cavity 24. Bolt 50 istightened until the appropriate amount of force is applied to therearward surface 38 of block 20. The remaining mold structure isprepared for casting and molten metal is then forced upwardly throughingate 30 into casting cavity 24. As molten metal contacts block 20,cavity defining surface 40 tends to elongate more rapidly than theportions of block closer to rearward surface 38 proximate tie rods 60and 62. The portions of block 20 near cavity defining surface 40 areunder compressive stress while the portions closer to rear surface 38are under a tensile stress. Since the material near surface 40 is at ahigher temperature than the portions of block 20 closer toward rearsurface 38, surface 40 has less strength and is therefore subject tocompressive yielding. If such compressive yielding is allowed to exist,when block 20 cools, surface 40 will be shorter than the portion ofblock 20 closer to rear surface 38 causing block 20 to become concave.

Compressive yielding is resisted in block 20 by the slots 36, the shimsand the tie rods 60 and 62. The slots 36 reduce the area in whichcompressive yielding may occur. The tie rods 60 and 62 provide thenecessary force to keep block 20 substantially straight along cavitydefining surface 40 by resisting the stresses which tend to open slots36. The force exerted by the tie rods 60, 62, to a certain degreefurther acts in such a way that a fulcrum is created by each shim at theend of each slot 36 proximate the corresponding hole 42. The forceacting about these fulcrums has a tendency to counteract the shrinkagethat normally would occur at surface 40 when block 20 cools.

I claim:

1. In a mold assembly having a plurality of inner blocks interengagedbetween a pair of side blocks to define a casting cavity, one of theinner blocks being a slotted metallic block having a plurality of spacedtransverse slots extending from a rearward surface of the slotted blockinwardly toward a forward cavity defining surface of the slotted blockintermediate first and second end surfaces for more than one-half thewidth of the slotted block, a tie rod assembly comprising a first lugconnected to a rearward portion of the slotted block proximate the firstend surface, a second lug connected to the rearward portion of theslotted block proximate the second end surface, and a tension meansinterconnected to the first and second lug for applying force to saidrearward surface to resist the stresses which tend to open the slots'and warp said block during thermal expansion and contraction.

2. A mold assembly according to claim 1 wherein the first lug is locatedintermediate the first end surface and a slot adjacent the first endsurface and the second lug is located intermediate the second endsurface and a slot adjacent the second end surface.

3. A mold assembly according to claim 1 wherein the tension meanscomprises spaced tie rods having first and second ends, a trunnion isconnected to the first ends of the spaced tie rods, and adjustablefastening means are engaged with the first lug and the trunnion to movethe trunnion toward the first lug to place tensional stresses on the tierods.

4. A mold assembly according to claim 3 wherein pin means interconnectthe second lug and the second ends of the tie rods.

5. A mold assembly according to claim 4 wherein the first lug is locatedintermediate the first end surface and a slot adjacent the first endsurface and the second lug is located intermediate the second endsurface and a slot adjacent the second end surface.

6. A mold assembly according-to claim 1 wherein the rearward portion ofthe slotted block has a groove located therein and extendingsubstantially along the length of the slotted block, a plate is locatedin the groove, and pin means secure the plate to the slotted block, thepin means being located intermediate adjacent slots.

7. A mold assembly according to claim 1 wherein holes are located at theinner end of each slot, and a shim is located in each slot, the shimextends from the rearward surface of the slotted block to the hole andhas a thickness generally equal to the thickness of the opening of theslot.

1. In a mold assembly having a plurality of inner blocks interengagedbetween a pair of side blocks to define a casting cavity, one of theinner blocks being a slotted metallic block having a plurality of spacedtransverse slots extending from a rearward surface of the slotted blockinwardly toward a forward cavity defining surface of the slotted blockintermediate first and second end surfaces for more than one-half thewidth of the slotted block, a tie rod assembly comprising a first lugconnected to a rearward portion of the slotted block proximate the firstend surface, a second lug connected to the rearward portion of theslotted block proximate the second end surface, and a tension meansinterconnected to the first and second lug for applying force to saidrearward surface to resist the stresses which tend to open the slots andwarp said block during thermal expansion and contraction.
 2. A moldassembly according to claim 1 wherein the first lug is locatedintermediate the first end surface and a slot adjacent the first endsurface and the second lug is located intermediate the second endsurface and a slot adjacent the second end surface.
 3. A mold assemblyaccording to claim 1 wherein the tension means comprises spaced tie rodshaving first and second ends, a trunnion is connected to the first endsof the spaced tie rods, and adjustable fastening means are engaged withthe first lug and the trunnion to move the trunnion toward the first lugto place tensional stresses on the tie rods.
 4. A mold assemblyaccording to claim 3 wherein pin means interconnect the second lug andthe second ends of the tie rods.
 5. A mold assembly according to claim 4wherein the first lug is located intermediate the first end surface anda slot adjacent the first end surface and the second lug is locatedintermediate the second end surface and a slot adjacent the second endsurface.
 6. A mold assembly according to claim 1 wherein the rearwardportion of the slotted block has a groove located therein and extendingsubstantially along the length of the slotted block, a plate is locatedin the groove, and pin means secure the plate to the slotted block, thepin means being located intermediate adjacent slots.
 7. A mold assemblyaccording to claim 1 wherein holes are located at the inner end of eachslot, and a shim is located in each slot, the shim extends from therearward surface of the slotted block to the hole and has a thicknessgenerally equal to the thickness of the opening of the slot.